1. Field of the Invention
The present invention relates to a shutter for preventing double insertion and a disc player mounting the same, more particularly, to a shutter for preventing double insertion of a disc by means of a simple machinery mechanism and a disc player having the same.
2. Description of the Prior Arts
In general, disc players can record information on and/or reproduce information from discs of magnetic or optical type such as optical video disc, digital audio disc, or compact disc, etc. There are several methods for loading the discs into the player and unloading them therefrom. A disc player of the front loading type wherein a tray having the disc mounted thereon is moved in the horizontal direction and then downward in the vertical direction thereby causing the disc to be mounted above a turntable is disclosed in U.S. Pat. No. 5,025,339 (issued to Kanno et al.). A disc loading device used in that of a front loading type is frequently employed. Recently, the disc player continues to be developed, especially the disc player of such a front loading type is greatly being developed.
The conventional disc player of the front loading type will be described in detail with reference to FIGS. 1 and 2.
FIG. 1 is an exploded perspective view for showing a conventional disc player of the front loading type. FIG. 2 is an enlarged sectional view for showing a pressing unit in FIG. 1. As shown in FIG. 1, reference numeral 10 denotes a disc tray for receiving a disc cartridge. Lower ends of side walls 12 of disc cartridge 10 are inwardly bent to form cartridge support pieces 14 for supporting the disc cartridge to be inserted thereinto or ejected therefrom. A tray guide rod 16 is formed on the outer surfaces of side walls 12 of disc tray 10. A moving plate 20 is provided with guide grooves 26 and guide rods 28 which are placed on its side walls. Guide rods 28 which are provided on the left and right sidewalls of disc tray 10 can slide along guide groove 38 while being inserted thereinto so that disc tray 10 can be moved into and from the housing. When loading and unloading the disc cartridge carried by disc tray 10 and moving plate 20 on the turntable, guide rod 28 can be slidably provided within and along guide groove 38 formed on the side walls of loading unit B supporting disc tray 10 and moving plate 20.
Pressing unit P is provided over loading unit B. Pressing unit P has a cone arm 91 which is generally of an elongated plate shape and is extended from the upper portion of the front of loading unit B to a position corresponding to the center of loading unit B. A cone disc 93 supported at the tip end of cone arm 91 is located above the center of loading unit B. Thus, when tray 10 moves horizontally together with moving plate 20 during the loading operation, cone arm 91 gradually moves pivotally downward, and then when tray 10 moves vertically downward, cone disc 93 is moved vertically downward to be located at its lowermost position so that it can press the disc. As shown in FIG. 2, an angle member 92 is fixedly attached to cone arm 91 near the proximal end thereof with its portion extending downward. When the disc is in a loaded state, angle member 92 is moved downward together with cone arm 91 due to the pivoting and downward movements of cone arm. Therefore, this angle member acts as a stop member when inserting another disc so that the double insertion of the disc can be prevented.
Meanwhile, below loading unit B there are provided a spindle assembly 23 for rotating the disc mounted thereon and a pickup apparatus for reading and writing information from the disc which is rotated by the spindle assembly with the movement in the radial direction of the disc under the disc. The disc player is provided with a loading drive system (not shown) which has a loading motor, a transmittance gear and a moving plate carrying gear for driving the loading unit, and is provided with a power supply unit (not shown) for transmitting a driving force to pickup apparatus 24. Disc tray 10 and moving plate 20 are guided along guide grooves 38 formed in loading unit B by the power supply unit and the loading drive system in the front loading method to load and unload the disc on the turntable.
However, in the conventional disc player having the above structure, the member for preventing double insertion is liable to shake or break. Furthermore, since the above member is in close connection with the disc on the turntable, if one tries to insert another disc while reading or reproducing information from a disc, impacts affect directly the original disc to deteriorate the reliability of products. Moreover, while loading and unloading the disc cartridge on the turntable, the carrying operation of the tray is performed by means of the loading drive system (provided with the loading motor, the transmittance gear and the moving plate carrying gear) and the moving plate, so that the internal structure of the disc player has become complicated. Further, due to heavy and large-sized products, this conventional structure goes against the recent trends relating to the miniaturization of the disc player.